Chair backrest mounting device

ABSTRACT

A chair backrest mounting device includes a main body, a middle fixing seat, and two side fixing seats. The main body is made of a flexible material. The middle and side fixing seats are made of a rigid material and embedded in a middle portion and two opposite end portions of the main body, respectively, so that the chair backrest mounting device can maintain sufficient flexibility and deformability to bear forces applied thereto in different angular directions, and sufficient rigidity to avoid easy elastic fatigue and breaking of the main body. Moreover, joint faces between the flexible main body and each of the rigid middle fixing seat and side fixing seats are non-flat faces to provide increased contact area and enhanced joining strength.

FIELD OF THE INVENTION

The present invention relates to a part for a chair, and more particularly to a chair backrest mounting device for connecting a chair backrest to a backrest support.

BACKGROUND OF THE INVENTION

FIG. 1 shows a conventional chair backrest mounting device in the form of an L-shaped bracket 1 having two arms. The L-shaped bracket 1 is provided on the two arms with a plurality of through holes 2, through which fastening elements 3 can be screwed into a backrest and a seat to connect the two parts to each other. The above-structured chair backrest mounting device is functionally restricted by the material of the L-shaped bracket 1. In the case of a material with relatively poor elasticity, it is uneasy to change an angle contained between the backrest and the seat via the L-shaped bracket 1, and the L-shaped bracket 1 does not allow adjustment of the backrest to different inclinations according to the sizes and weights of different users for the users to sit on the chair comfortably. On the other hand, in the case of a material with relatively good elasticity, the L-shaped bracket 1 tends to have insufficient structural strength at the bend and the through holes 2, at where the fastening elements 3 are extended through. Thus, the L-shaped bracket 1 will break at these positions due to elastic fatigue when the chair has been used over a long period of time.

It is therefore tried by the inventor to develop an improved chair backrest mounting device that has sufficient flexibility and deformability to bear external forces applied thereto from different angular directions, and also sufficient rigidity to avoid easy elastic fatigue and breaking at portions having fastening elements extended therethrough and to provide enhanced binding strength.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a chair backrest mounting device that has sufficient flexibility and rigidity to support a chair backrest and is durable for use.

To achieve the above and other objects, the chair backrest mounting device according to the present invention includes a main body, a middle fixing seat, and two side fixing seats. The main body is made of a flexible material. The middle and side fixing seats are made of a rigid material and embedded in a middle portion and two opposite end portions of the main body, respectively. The middle fixing seat is provided with a central through hole to serve as a middle mounting hole, and the side fixing seats each are provided with a central through hole to serve as a side mounting hole. Moreover, joint faces between the flexible main body and each of the rigid middle fixing seat and side fixing seats are non-flat faces to provide increased contact area and enhanced joining strength.

With the above arrangements, the chair backrest mounting device according to the present invention is durable for use and can strengthen the chair backrest.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is a perspective view of a conventional chair backrest mounting device;

FIG. 2 is a perspective view of a chair backrest mounting device according to a first preferred embodiment of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is a phantom perspective view showing the chair backrest mounting device of the present invention connected to a chair backrest;

FIG. 5 is a sectioned side view showing the chair backrest mounting device of the present invention connected to a chair backrest;

FIGS. 6 and 7 show the chair backrest mounting device of the present invention connected to a chair backrest is deflected under force applied thereto in different angular directions;

FIG. 8 is a sectioned side view of a chair backrest mounting device according to another embodiment of the present invention having serrated joint faces between a main body and fixing seats thereof; and

FIG. 9 is a sectioned side view of a chair backrest mounting device according to a further embodiment of the present invention having fluted joint faces between a main body and fixing seats thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIG. 2 that is a perspective view of a chair backrest mounting device according to a first preferred embodiment of the present invention, and to FIG. 3 that is a sectional view taken along line A-A of FIG. 2. As shown, the chair backrest mounting device includes a main body 10, a middle fixing seat 20, and two side fixing seats 30.

The main body 10 is made of a flexible material, so that the chair backrest mounting device is deformable when it is subject to external forces applied thereto in different angular directions.

The middle fixing seat 20 is made of a rigid material and is embedded in a middle portion of the main body 10. The middle fixing seat 20 is internally provided a central through hole to serve as a middle mounting hole 22 for a fastening element (not shown in FIGS. 2 and 3) to extend therethrough. In an operable embodiment, the middle mounting hole 22 is internally threaded and the fastening element is externally threaded to mesh with the middle mounting hole 22.

The middle fixing seat 20 made of a rigid material provides sufficient structural strength to avoid easy elastic fatigue and breaking of the main body 10 at the middle mounting hole 22 due to deformation of the main body 10 under external force over a long time.

The side fixing seats 30 are also made of a rigid material and are separately embedded in two opposite end portions of the main body 10. The side fixing seats 30 each are internally provided a centered through hole to serve as a side mounting hole 32 for a fastening element (not shown in FIGS. 2 and 3) to extend therethrough. Pointed teeth 34 are spaced on a front face of each of the side fixing seats 30. In an operable embodiment, the side mounting holes 32 are internally threaded and the fastening elements are externally threaded to mesh with the side mounting holes 32.

Similarly, the side fixing seats 30 made of a rigid material provide sufficient structural strength to avoid easy elastic fatigue and breaking of the main body 10 at the side mounting holes 32 due to deformation of the main body 10 under external force over a long time.

Joint faces 12 between the flexible main body 10 and each of the middle fixing seat 20 and the side fixing seats 30 are non-flat faces to provide an increased contact area and ensure enhanced joining strength between the main body 10 and the fixing seats 20, 30. In the illustrated first preferred embodiment, the joint faces are wave-shaped faces.

Please refer to FIGS. 4 and 5 that are perspective and sectioned side views, respectively, showing the chair backrest mounting device of the present invention connected to a chair backrest. As shown, the chair backrest mounting device is located between a backrest support 5 and a chair backrest 6, and is connected to the backrest support 5 by rearward threading a fastening element 4 through the middle mounting hole 22 into the backrest support 5, and connected to a rear side of the chair backrest 6 by forward threading another two fastening elements 4 through the side mounting holes 32 into the chair backrest 6. At this point, the pointed teeth 34 on the front faces of the side fixing seats 30 are firmly engaged with the rear side of the chair backrest 6, preventing the chair backrest mounting device from moving or sliding relative to the chair backrest 6.

FIGS. 6 and 7 show the chair backrest mounting device of the present invention connected to the chair backrest 6 is deflected under forces applied thereto in different angular directions. When a user applies forces to the chair backrest 6 in different angular directions, the flexible main body 10 allows the chair backrest mounting device of the present invention to maintain sufficient flexibility and deformability to bear force applied thereto in different angular directions, and the rigid middle and the side fixing seats 20, 30 allows the chair backrest mounting device of the present invention to maintain sufficient rigidity to avoid the portions of the main body 10 being extended through by the fastening elements 4 from becoming elastic fatigue and broken easily. Moreover, the non-flat joint faces between the flexible main body 10 and the rigid middle fixing seat 20 and side fixing seats 30 provide increased contact area and enhanced joining strength, allowing the chair backrest mounting device of the present invention to have prolonged service life.

FIG. 8 is a sectioned side view of a chair backrest mounting device according to another embodiment of the present invention. In this embodiment, the joint faces 12 between the main body 10 and the middle and side fixing seats 20, 30 are serrated faces to provide increased contact area and enhanced joining strength.

FIG. 9 is a sectioned side view of a chair backrest mounting device according to a further embodiment of the present invention. In this embodiment, the joint faces 12 between the main body 10 and the middle and side fixing seats 20, 30 are fluted faces to provide increased contact area and enhanced joining strength.

The present invention is novel, improved and industrially practical for use because it includes rigid fixing seats embedded in the flexible main body at portions that are relatively easy to break, so that the chair backrest mounting device can maintain sufficient flexibility and deformability to bear forces applied thereto in different angular directions, and sufficient rigidity to avoid easy elastic fatigue and breaking of the main body. Moreover, the non-flat joint faces between the flexible main body and the rigid middle fixing seat and side fixing seats provide increased contact area and enhanced joining strength. It is anticipated products derived from the chair backrest mounting device of the present invention can fully meet market demands in terms of its industrial applicability.

The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. A chair backrest mounting device, comprising: a main body being made of a flexible material; a middle fixing seat being made of a rigid material and embedded in a middle portion of the main body, and the middle fixing seat being internally provided a central through hole to serve as a middle mounting hole; and two side fixing seats being made of a rigid material and separately embedded in two opposite end portions of the main body, and each of the two side fixing seats being internally provided a central through hole to serve as a side mounting hole; wherein joint faces between the main body and each of the middle fixing seat and the side fixing seats are non-flat faces, which provide increased contact area and accordingly enhanced joining strength between the main body and the fixing seats.
 2. The chair backrest mounting device as claimed in claim 1, wherein the middle and the side mounting holes are internally threaded.
 3. The chair backrest mounting device as claimed in claim 1, wherein the side fixing seats each are further provided at a front face with a plurality of spaced pointed teeth.
 4. The chair backrest mounting device as claimed in claim 1, wherein the non-flat joint faces between the main body and each of the middle and the side fixing seats are wave-shaped faces.
 5. The chair backrest mounting device as claimed in claim 1, wherein the non-flat joint faces between the main body and each of the middle and the side fixing seats are serrated faces.
 6. The chair backrest mounting device as claimed in claim 1, wherein the non-flat joint faces between the main body and each of the middle and the side fixing seats are fluted faces. 